ORH_wxman

Pattern change set in during early Dec 2010....here's what it looked like for 16 days Dec 5-20, 2010.....BOS, ORH, and PVD all had zero measurable snow during this 16 day stretch. BDL had 0.3" from a squall I think. This isn't trying to scare anyone, but it reiterates that great patterns can sometimes not produce, or take a while to produce. WE know it eventually went gangbusters, but it didn't happen right away. OTher years like 1995 it happens almost right away.

I still think we need to watch the follow up wave (Dec 9…maybe as early as Dec 8 or late as Dec 10) for something. It wouldn’t be huge but it could be one of those fast movers if things align.

People want clown maps that show good snow. That’s really what the anxiety is all about. Deep down many won’t admit that it’s the OP runs not showing blizzards is what is concerning to them….it’s not the ensemble mean they are concerned about. You’d think it wouldn’t be that way since most posters here have been on these forums for years (if not decades).

The control run was more for me and Tip

Ray ran P16 member from his basement

The Pacific look keeps changing in that Dec 8-13 time range. Most of the storm threats are going to be from the pacific as shortwave eject out and underneath the block....and there's the added complexity of the central/southeastern ridge in the process of retrograding westward which also mucks up the ability for guidance to show a lot of continuity in handling shortwave traversing the flow. So basically we get: Atlantic ---> Stable on guidance Pacific ---> Volatile on guidance CONUS ---> Semi-volatile on guidance Not a good recipe for getting consistent storm threats showing up on model guidance.

PAC almost looking slightly El-Ninoish at the end. Subtle drop in heights SW of Aleutians and pumping of heights over AK and PNA ridge region.

This is prob not far from the truth. Not uncommon at all for models to be all over the place until much closer on individual storm threats. Esp in a high blocking pattern.

Retro storm in clown range on Euro today. You’re gonna see plenty of weird solutions that appear and disappear from cycle to cycle with this pattern.

He really needs to move out west with some elevation....that's where the seasons match the solar insolation the most. We're significantly more lagged here.

Yeah it's definitely about 300-400 miles south of yesterday's 12z run. Not sure it means much though....EPS didn't trend with the block between 12z and 00z...so I'd want to see other guidance do it too.

GGEM was a close miss for Dec 9th....prob gonna be a lot of large run to run swings on these threats more than a week out.

Yeah it was intriguing that it was trending colder, but now that the trend sort of stopped....it's pretty meh. It was always tougher for us too vs NNE.

Dec 1961 had an epic one on Xmas eve that ended predawn hours Xmas morning. Much of the interior from ORH-eastward had 18-20+, but even the coast did well until you got to the south coast and Cape.

PNA spike is what you’ll want to look for when trying to get a big dog storm. We typically don’t have big dogs without a PNA ridge spike. It’s possible (like 1/12/11) but not common. Events will typically be more of the fast movers and quick redevelopers when it’s -PNA/-NAO

The following Decembers had at least one day where the AO reached -4 SD (dataset goes to 1950) 2009 1976 2010 2000 1968 1963 1950 1995 1978 1962 1966

It can go well too…..Feb 22-28, 1969

Yeah I bet we’ll have a few runs between now and end of next week that show some ridiculous solutions out in clown range. Fwiw, not exactly same evolution but the “blocky fujiwara” type development happened in the already-mentioned Dec ‘81 storm http://www.meteo.psu.edu/fxg1/NARR/1981/us1206.php#picture

It’s not just that +20 didn’t continue, we reversed the departures and were below normal for the better part of 2 weeks. I’m not sure how Bretton Woods not being buried by the end of November is relevant to the discussion outside of ski enthusiasts who were planning a trip for 11/28-30 when we warmed back up. There were already plenty of ski resorts opening during that pattern shift posted in the ski thread so they took advantage for sure. Let’s not play the anecdotal game where any of us can write a narrative. Sticking to empirical metrics, the pattern was very different on a large scale than the beginning of the month. The numbers are what they are.

NAO blocks can reload too after a period of decay. That definitely happened in 2010-2011…even after the monster block (with a couple reloads) finally broke down after the 1/12/11 storms, we got some mini-reloads…a more east-based block formed ahead of the 1/27/11 system.

By definition a block is decaying as soon s it reaches peak strength. But the decay stage can last a long time...even weeks sometimes. Sometimes you get little reloads too.

Yeah and I wonder if we get multiple shots at this....that first window is still kind of early in the pattern. Historically, the better shot would be when the block is kind of decaying which would be more like beyond 12/15. But we've seen multiple storms before in a big NAO block regime. Feb 2021 is one example....March 2018 is another.

That look around Dec 12-13 is starting to get really good....not just general pattern-wise...but that's very threatening for a big system when you get the Rockies ridge popping coinciding with the Atlantic look there

Dec 1960 was one of the all time early season KU doozies, but it wasn’t the same pattern as we have coming up. Didn’t have an NAO block. It did have a temporary 50/50 low though which is what the NAO blocks usually help out with (keeping the 50/50 low in place)…and huge western ridge that went all the way up the Arctic Ocean.